Combination low pressure feed heater



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Aug. 31, 1943. 4 E. PfwoRTHEN COMBINATION LOW PRESSURE FEED HEATER Filed July 25; 1941 Patented Aug. 31, 1943 NlflE D "STATES PATENT OFFICE x 1 COMBINATION LOW PRESSURE 1 HEATER 1 I 1 Eugene Porter Worthen, East Weymouth, Mass,

FEED

1 assignor, by mesne assignments, to Buena Vista Iron Company, a corporation of New Jersey 1 1 Application July 25,1941,S erialNo. 404,011

1 1 This invention relates to a combined low pressure feed heater embodying in one unit aplurality of auxiliary heat exchangers suitable for marine use. 1 1 1 i 1 1 Modern high pressure steam plants with three or more stagesof feed heating comprise usually a large number of individual heat exchangers; which in most cases include the following; (a)

main air ejector inter and after condensers; (b)

auxiliary airejector inter and after condensers;

(c) turbine gland leakoflcondenser; (6) feed heater drain cooler; (e), first stage feed heater; (I) second stage deaerating heater; and (g) third stage feed heater. Each ofthese has its separateshell, heads, interconnecting piping, by-

.pass piping and valves, which are always expensive to furnish and maintain, and in marine installations particularly, are excessivelywasteful ot valuable space and weight. A great deal of 1 heat escapes unused because of theexposure of 1 broad radiating surfaces, thus requiring unnecessarily largeexpenditures for fuel and additional expense for insulating; coverings. 1 Also, it is sometimes adiflicult .propositionto keep a feed heater properly drained and,dry, while completely flooding its. drain cooler at the sametime,

low pres sure heater, and more particularly to a combined Claims (01.257-2) Fig. 5 is a section taken along the lines 5-5 01 Fig. 4 and showing in detail the air ejector cornpartment. g n 1 1 Fig. 6 is a section alongthe lines 6-6 of Fig. 4 showing the feedheater drain cooler.

Fig. 7 is a section along the lines l-l of Fig. 4

, showing the auxiliary airejector intercondenser.

yetboth conditicnsare necessary for the most eflicient operation. M i 1 One object of my invention is, therefore, to provide aclosed typelowpressure feed heater employing straight tubes and combining within a single shell firstmstagel feed heater, combined gland leakoff condenser and main and auxiilary after condenser, feed heaterdrain cooler, and auxiliary air ejector intercondenser.

Another object is a combination low pressure unit which insures flooding the drain cooler while keeping the feed heater dry. 1 1

Another objectis acheaper andmore compact heat exchange system with much less piping and fewer valves and other parts than conventional systems If Still another object isajlow pressure heat exchange sys temsuitable and adapted .for marine use.

. Numerous other objects and advantages will be apparent from the following description, wherein reference is made to the accompanying seven sheets of drawings illustrating the invention and wherein like numerals of reference indicatelike is a front elevation of the five-section Fig. 8 is a section taken alongthe lines 8 8 ofFig. 4.

Fig. 9 is an end view of the outlet end tube sheet.

Fig. lOis an end view of the retum end tube sheet.

Fig. 11 is a functional diagram, of the above apparatus showing by legends and arrows the course of the condensate therethrough.

Referring now also to the drawings, Figs. 1

to 11, inclusive, show a closed type unit comprising within one'shell I the auxiliary air ejector interoondenser 2, the mainair ejector intercom denser 3, the feedheater drain cooler 4, the combined main and auxiliary after condenser and gland leakoff condenser 5, airejector compartment 6, and the first stage feed heater 1, which are arrangedfrom bottom to top within the shell in the order named. In addition flanged first and second stage mainand auxiliary air ejectors 8, 9;

lil and II, and motor-driven exhaust fan i2, with' associated piping and valves are externally mounted onthe" unit.

, The shell or casing l is constructed of Welded steelfplate, and preferably is rectangular in made cross-section as shown, although it may be in circular or other form if desired.

Outlet and return tube sheetsl3 and M (Figs.

9 and 10) are welded to their respective endsof the shell I, and horizontal division plates I5, l6,

l1, "l8 and 19 welded all around to the "shell and to the tube sheets for pressure tightness separate the different sections of the" unit. Since the condensing sections of the unit are required to: operate under partial vacuum, the main and auxiliary intercondensers' 2 and {and combined main and auxiliary air ejector after condenser and gland leakofl condenser, 5 must be particu larly tested and checked for tightness under Each'individualtube in tube banks 20 ,2l, 22, 23, 24, 25,126, 21, 28, 29,3D, 3| ,132 and, 33 is secured at oneend by belling or thelike,

pressure.

into a tube-sheet and packed with any suitable packing into the tube sheet ,at the other .endto permit free expansion of shell andtubes. It is, of course obvious that .both ends may bepacked if desired Staggered verticalbaflf'le-plates 34 35,

38, 31 and 38 are weldedas sho'wnlin each section except airejector compartment 6, and are suitably perforated with, slightly oversize and therethrough without binding or chafing.

Return waterhead 39. and outlet waterhead 4U rounded edge holes to allow passage of the tubes are bolted or otherwise'secured to tube sheets unit connection 61, recirculating connection and vent 69.

Grooved portions Ill, H, I2, 13,14; '15 and 1t on tube sheet I3 and corresponding division walls Fl, 78, I9, 8B, 8!, 82 and 83 in outlet waterhead t!) form chambers 84, 85, 8B, 81, 88, 89, 9B and 9!. Drain 92, main condensate inlet 93, tapped thermal unit connection 94, and combined condensate outlet 95 are also provided on said waterhead #0. The conventional combinations of thermostat and thermometer shown diagrammatically in Fig. ll comprises the thermal units which screw into tapped connections 61 and 94.

The auxiliary air ejector intercondenser 2 is provided with port $6 for first stage air ejection and port 91 for second stage air ejection and with relief valve connection 33 and drain outlet 59. The main air ejector intercondenser 3 is similarly provided with port Iiiil for first stage air ejection and ports IN and I02 for second stage air ejection and with relief valve connection I03 and drain outlet IIM;

Feed heater drain cooler 4 is supplied with inlet port H35; clean out plug Hi6 and drain outlet standard trap or float controlled type equipped construction utilizes available space not otherwise used; and avoids increasing the dimensions of the complete unit which would occur if these connecting pipes were led, say, above or below the outside of the casing.

In the top of shell I at one end of first stage feed heater I is located bleeder steam port I with perforated inlet plate I3I in the 'bottom opening thereof. Drain outlet I32 in the side nects by pipe I to drain regulator III], which with water glass IH, mounted on the side of the inlet port H2 in division plate) at the top,

thereof, and with gland inlet port H3 centrally on one side and drain outlet H4 at the opposite end from inlet port I I2. Adjacent to drain outlet !M is gland exhaust port H5, which is connected by pipe H5 to exhaust fan I2 supported on foundation H1.

Through air ejector compartment 6 run parallel horizontal pairs of pipes H8 and H9 connecting on one side to first stage main and auxiliary air ejector 8 and 9 and on the other side connectingv throu h angle valves It!!! and IZI and pipes I22 and 123th ports I09 and 96 on main and auxiliary air ejector intercondensers 3 and 2 respectively- The second sta e pairs of main and i the air ejector compartment 5 is primarily one.

of compactness. For best utilization of space thevarious pipes and valves are arranged on both sidewalls of the casing; and it is necessary to connect the discharge from the first stage main and auxiliary air ejectors 8 and 9' on one side to the pipes. I212 and I23 leading to the main and auxiliary intercondensers 3 and 2 on the other. By leading theconnecting pipes H8 and H9 through the air ejector compartment 6 the in turn connects by pipe I36 to port I31 in said half-pipe.

In operation, the combined unit receives condensate directly from, the main and auxiliary condensate pumps (not shown), directs the flow of condensate in propersequence through the passes of the tube banks, and discharges to thesecond stage deaerating; feed heater (also not shown). Condensate from the main condenser enters inlet 93 in waterhead 40 and condensate from the auxiliary or dynamo condenser enters inlet 35 in opposite waterhead 39. The main condensate flows through tube banks 24 and 25 of the main air ejector intercondenser 3 and the single bank 25 of the feed heater drain cooler 4 while the auxiliary condensate flows through the banks 20, 2I, 22' and 23 of the auxiliaryair ejector intercon d enser 2 and by-passes the main air ejector intercondenser 3 and drain cooler 4 by means of vertical by-pass plate in return waterhead '39 to combine with'the main con-' densate in chamber 62 in said waterhead 39 at the entrance to the first pass of the combined main and auxiliary air ejector-and gland leakofi condenser 5. The total condensate then flows through the two tube passesZ'I and 28 of that section and the five passes 29, 30, 3|, 32 and 33 of the first stage feed heater I to combined condensate outlet in outlet waterhead 43.

The feed heater section 1 of the combined unit 3 receives heating steam from the bleeder on the low pressure turbine (not shown) which at full power will maintain a pressure in the heater shell of about 8.5 pounds per square inch absolute. Steam enters by port I30 through perforated inlet plate I3I designed to prevent direct impingement of high velocity steam or water upon the tubes therein, and then is directed several times across the said'tubes by internal vertical bafiie-plates 38. Feed heater drains are conducted by drain outlet I32 through half-pipe I33 to inlet port I05 opening into drain cooler 4. After traversing the passes of the baflle plates 36 in the said drain cooler, the cooled drains are discharged to the main condenser (not shown) through float-controlled drain level regulator [Ill and throttle valve )9 mounted on the side of the unit and arranged to maintain a' level ofv drains in half-pipe I33 approximately midway between feed heater I and drain cooler 4, asshown by water glass II'I, thereby keeping feed and 9 take suction from their respective condensers (not shown), and discharge into horizontal pairs of pipes H8 and H9 respectively running through air ejector compartment 6 to the opposite side of the shell where the discharge is regulated by angle valves I'Zlland I2! 1 on pipes I22 and I23 leading to portslflfl and 96 through port H5.

on themain and auxiliary. air ejector intercondensers 3 and 2 respectively. m

Second stage main. andauxiliary air ejectors I and II take suction from ports IOI, I02 and 91 on their respective intercondensers 3 and 2 through external pipes I26 and I21 fitted with gate-valves I24 and I25, and discharge into air ejector compartment 6 which serves as an entrance chamber tothe combined gland leakoff and air ejector after condenser 5. Connection between this entrance chamber and theabovementioned condenser is through port H2; at one end of the division plate I8 separating these two compartments; and the provision of an air ejector compartment separate rmm the con--.

denser compartment is an effective way to lead the steam into the condenser at the proper point for most eflicient use.

The air and vapor mixture from the air ejectorsthen makes five passes across the tubes 21 and 28 through the bailie-plates 31 in said gland leakoif and air ejector after condenser 5, be-

fore combining with the vapors from the turbine glands (not shown); which enter through gland inlet port I I3in the side of shell I. The combined vapors then tr'averse the remaining six passes through saidbafile-plates 31 to exhaust port at the other end, where the mixture, principally air at that point, is withdrawn through pipe II6 by exhaust fan I2 and discharged to atmosphere.

The separation of airand vapor from the condensate in the combined gland leakoftand air ejector after condenser 5- is by gravity. The

baffle-platesprovided in the condenser compartment constrain the steam and air to flow across the tubesa number of times so as to produce emcient condensation. The drops of water fall to the bottom of the compartment and are drained or! through the outlet I I4. The air, and so much of the vapor as is not condensed, are discharged to atmosphere by the fan suction Drains from the main and auxiliary air ejector intercondensers 3 and 2 and combined air ejector after condenser and gland leakofi condenser 5 flow from drain outlets I04, 99 and H4 through suitable pipes to the fresh water drain collecting tank (not shown). In each caseparallel flow of drains and vapor is effected by locating the drain outlet thereof at the opposite end from the vapor inlet. a

At low power, with small quantities of condensate available, provision ismade formaintaining sufiiciently low temperature, 1. e., under 1230f F., in the combined air ejector after condenser and gland leakoff condenser 5, to condense and air ejectors as aforesaid by recirculating part of the condensate from the last pass of the emciently the vapors coming from turbine glands :combined gland Ieakoif and air ejector intercondenser 5 through connection 68 to either the main or the dynamo condensers. a

The amount of such recirculation is controlled by the temperature of condensate leaving the:

main. and the auxiliary air ejector intercondensers 3 and 2 respectively by the thermostats in the thermal units located at 61 and 94 in the waterheads, which are set to operate at about 120? F. Althoughthe recirculated condensate passesthrough the drain cooler 4 ahead of the combined gland leakoff and air ejectorafter condenser 5 there islittle or no heating of the condensate in the drain cooler 4 at low power because under that condition the steam supplied to densate, an auxiliary air ejector intercondenser having tube passes for thefiow'of auxiliary condensate, a vertical by-pass plate closing one end the first stage feed heater1 from the bleeder on the low pressure turbine is at 'verynearly the.

same temperature and pressure as the exhaust to the main condenser and hence the drains goin to the drain cooler 4 from the first stage heater 1 are only slightly above the temperatureof the condensate leaving the condenser. sate entering the drain cooler may be at the same or even higher temperature than the drains since at that point it has. already received some heat from the air ejectorintercondensers.

Under port conditions with. the main turbine shut down, the unit is left in the feed circuit, the condensate from the dynamo condenser then ervingto condense the vapors from the auxiliary. air ejectors and from the generator turbine glands. The feed heater 1 and drain cooler 4- aswell as the main air ejector intercondenser 3 are inoperative under those conditions.

Should itbecome necessaryto shut downthe unit for repairs the condensate may be bypassed to thesecond stage deaerating heater, though with some loss' in over-all efficiency. During the shut-down period the vapor from the turbine glands will be discharged to the engine room. A standby single stage air ejector which vantages in the way of compactness and efflciency, but it of course requires engine room space appropriate to itsshape and dimensions.

and auxiliary inter and afterrcondensers of any.

conventional type may be utilized withthe modified three-section unit shown in my divisional application, Serial No. 452,445 filed July 27, 1942,

as another form of my invention.

Although I have thus described my invention in considerable detail, I desire it 'to be clearly understood that I reserve the right to use such substitutions, modifications, or equivalents there;

of tissue embraced. withinthe scope and spirit of my invention, as defined in the appended claims.

Having thus describedmy invention what claim as new and useful anddesire' to secure by Letters Patentis: a

1. A combined feed heater unit comprising a main inlet port for receivingmain condensate", an auxiliary inlet port for receiving auxiliary condensatea main air ejector intercondenser having tube passes and a feed heater drain cooler having a tube pass for the flow of main 30011- of the main air ejector intercondenser and partially closing an end of the drainoooler for: by-

passing auxiliary cond ensate around the main air ejector intercondenser and the drain cooler;

a chamberwherein the main and auxiliary con densates combine, a combined air ejector after condenser and gland'leakofif condenser having tube passes for the flow of the combined con densate, a first stage feed heater having tube" passes for the flow and heating of said combined The conden-- Where two or'more somewhat small'or irregularspaces rather than one fairly large and regular .space are available, or where for any. other reason more than oneunit is deemed desirable, separate main condensate, and an outlet port for discharging the heated combined condensate.

2'. A combined unit having'straight' tubes for the passage of condensate and comprising a single enclosing shell, a feed heater section therein, an inlet connection for admitting steam thereto to heat the condensate, an air ejector compartment beneath the feed heater for receiving steam ejected from a separate source, a. combined air ejector after condenser and gland leakofi' condenser beneath the air ejector compartment for receiving and condensing steam from the air ejector compartment, a drain cooler thereunder forv receiving and cooling drains from steam condensed in the feed heater section, a main air ejector interoondenser beneath the drain cooler through which main condensate passes to said drain cooler, an auxiliary air ejector intercondenser beneaththe main air ejector intercom.

denser through which auxiliary condensate passes to combine with the main condensate at the entrance to the combined air ejector after condenser and gland leakoff condenser, means for conducting drains from steam condensing in the feed heater from the feed ,heater'to'the drain cooler, and means for controlling the discharge of drains from the drain cooler in response to the level of the drains in'the'conducting means.

3. In a multi-stage steam plant including separate main and auxiliary condensers, turbine glands, and fresh water drain collecting tank, the combination in a feed heater unit with an air ejector compartment, main and auxiliary intercondensers, and combined air ejector after condenser and gland leakofi condenser, of a plurality of'first stage main and auxiliary air ejectorsfor receiving air and vapor mixtures from the'main and auxiliary condensers respectively, separate means for carrying said mixtures through the air ejector compartment, separate means for conducting said mixtures to main and'auxiliary intercondensers respectively, separate second stage main and auxiliary air ejectors .for receiving said mixtures from the ,main and auxiliary intercondensers and injecting same for commingling in the air ejector compartment, means for discharging the commingled mixture into the combined air ejector after condenser and gland leakoff'condenser, means for admitting air and'vap'or from the turbine glands to join the previously commingled air and vapor mixture, an outlet for discharging the condensate and a separate outlet for discharging the air and vapor from the combined air ejector after condenser and gland leakofi condenser.

4. In a multistage steam plant including separate main and auxiliary condensers, turbine glands, and fresh water drain collecting tank, the combination in a low pressure feed heater unit with an air ejector compartment, main and auxiliary intercondensers, and combined air ejector aftercondenser and gland leakoff condenser, of apair of first stage main air ejectors for receiving main air and vapormixture' from the main condenser, parallel horizontal pipes for carrying said mixture therefrom through the air ejector compartment, valves. for controlling the flow of said mixture, joined external pipes for conducting the mixture to the main interoondenser, separate pipes for. conducting the mixture therefrom,

compartment, first stage auxiliary air ejectors for receiving auxiliary air :and vapor mixture,

from the auxiliary condenser, parallel horizontal pipes for carrying said mixture through the air ejector compartmenu valves for controlling the flow of said mixture, joined external pipes for conducting the mixture to the auxiliary intercondenser, diverging pipes for conducting said mixture therefrom, valves on said diverging pipes, a pair of second stage auxiliary air ejectors for receiving said mixture from said diverging pipes and injecting it into the air ejectorcompartment for commingling with the main mixture, a port for discharging the commingled mixture into the combined air ejector after condenser and gland.

leakoff condenser, a port for admitting air and vapor from the turbine glands to join the previously combined air, and vapor mixtures, an,

outlet for discharging condensate and a separate outlet for discharging air and vapor from the combined air ejector after condenser and gland leakoif condenser.

5. In a multi-stage steam plant including main and auxiliary condensers, second'stage deaerating feed heater, turbine glands and bleeder, and fresh Water drain collecting tank, a low pressure feed heater unit comprising a unitary containing shell substantially rectangular in transverse section, a plurality of horizontal division plates forming in order from the bottom rectangular compartments in said shell comprising an auxiliary air ejector interoondenser, a main air ejector intercondenser,

a feed heater drain cooler, a combined gland.

leakof condenser and main and auxiliary after condenser, an airejector compartment through which air and vapor pass to the combined gland leakoff condenser and main and auxiliary after condenser, and a first stage feed heater through Which heating steamirom the turbine bleeder passes to the feed heater drain cooler, a tube.

sheet secured at each open end of said shell, a.

water head for injecting condensate from the.

main condenser into the tubes in the main air ejector interoondenser and thence to the drain cooler, division walls in the Water heads to direct flow of main and auxiliary condensate sep arately through their respective tubes, a vertical by-pass Wall in the return Water head to by-pass condensate from the auxiliary air ejector intere condenser to combine with condensate from the drain cooler at the entranceof the combined gland leakoff condenser and main and auxiliary, air ejector section, a division Wall in return Water head to conduct. the combined condensate through the said gland leakoff condenser and main and auxiliary air ejector section, an out-v let for recirculating part of the combined con-- densate to the main, or auxiliary condensers,

thermostatic means for regulating the amount of condensate recirculated, the aforesaid first stage feed heater being adapted and arranged for heating the remaining condensate'and dis-- charging same.

EUGENE PORTER WORTI-IEN. 

